Mechanical ciphering units



Jan. 9, 1951 L. M. POTTS MECHANICAL CIPHERING UNITS Original Filed July5, 1946 6 Sheets-Sheet l FIG-2 INVENTOR LOUIS M. POTTS, DECEASED MARTHA'W. G. POTTS,EXECUTR|X BY {M 48M ATTORNEY Jan. 9, 1951 1.. M. POTTSMECHANICAL CIPHERING UNITS Original Filed July 5, 1946 6 Sheets-Sheet 2luvNToR LOUIS M. POTTS,DECEASEO MARTHA W. C. P OTTS,EXECUTRIX BY Z WZTTORNEY Jan. 9, 1951 L. M. POTTS 37,420

MECHANICAL CIPHERING UNITS Original Filed July 5, 1946 s Sheets-Sheet 5FIG. 8

D I m Q I I |NVENTOR LOUIS M. POTTS, DECEASED MARTHA W. C. POTTS,EXECUTRIX BY aw? ATTORNEY Jan. 9, 1951 L. M. POTTS 2,537,420

MECHANICAL CIPHERING UNITS Original Filed July 5, 194a e Sheets-Sheet 4i FIG. I0

INVENTOR LOUIS M. POTTS, DECEASED MARTHA W. C. POTTS. EXECUTRIX Zia, 0PM

ATTORNEY L. M. POTTS 2,537 ,420

MECHANICAL CIPHERING UNITS Jan. 9, 1951 6 Sheets-Sheet 5 Original FiledJuly 5, 1946 INVENTOR LOUIS M. POTTS, DECEASED MARTHA W. o. POTTS,EXECUTRIX ATTORNEY Jan. 9, 1951 L. M. POTTS.

MECHANICAL CIPHERING UNITS Original Filed July 5, 1946 6 Sheets-Sheet 6FIG. l5 my l65 I75 n2 I84 1 hi I" I l INVENTOR LOUIS M. POTTS,DECEASEDMARTHA w. c. POTTS,EXECUTR|X BY ORNEY Patented Jan. 9, 1951 MECHANICALCIPHERING UNITS Louis M. Potts, deceased, late of Evanston;-Ill., byMartha W. C. Potts, executrix, Evanston, Ill., assignor to TeletypeCorporation, Chicago, 111., a corporation of Delaware Originalapplication July 5, 1946, Serial No. 681,444, now Patent No. 2,504,044,dated April 11, 1950. Divided and this application November 5, 1948,Serial No. 58,504

This invention relates to secret'printing telegraph systems andparticularly to mechanical ciphering units for accomplishing theenciphering and deciphering of telegraph messages.

This application is a division of copending application, Serial No.681,444, "filed July 5, 1946 and which issued as Patent No. 2,504,044 onApril 11, 1950.

A chief object of the invention is the provision of mechanical cipheringunits for secret telegraph message communication;

Another object of the invention is the provision of mechanisms for usewith standard printing telegraph apparatus for performing cipheringoperations.

A further object of the invention is the provision of circuitarrangements which can be conveniently used with the cipheringmechanisms in standard printing telegraph-apparatus.

Other objects,.features and advantages of the invention will appear asthe description of the invention progresses.

The invention features the employment of key tape controlled codingmagnets for use with a.

combined telegraph transmitting and printing apparatus of the typedisclosed in the patent of S. Morton et al., 1,904,164, dated April18,1933. One set'of magnets is used to furnish kev signal codecombinations which combine with original or plain English signal codecombinations to encipher outgoing signals in a transmitter of the typedisclosed in the Morton et al. patent, in whichthe well known Baudotstart-stop system is uti ized. In the type of ciphering employed in theinstant invention a like condition of individual eements of the originalsignal code permutations and the individual elements of the key signalcode permutations resu t in a spacing signal. On the other hand, unlikeconditions of the elements result in a marking signal. For a moredetailed description of such a system, reference should be had to thecopending application Serial No. 462.522, filed October 19. 1942, in thename of Louis M. Potts and which issued as Patent 2,403,679 on July 9,1946. The set of coding magnets used with the transmitter operatemechanical elements which combine with mechanical elements controlledfrom the printer keyboard to ultimately determine the position of thetransmitting levers. For the printing operation a second set of codingmagnets are provided which control mechanical elements which combinewith the swords controlled from a selector magnet to ultimatelydetermine the position of the selector vanes of the printer.

9 Claims. (01. 17s-22) The code magnets for the transmitter andthereceiver are controlled by suitable circuit arrangements. For particularuse with this type of printing telegraph apparatus an additional circuitis provided whereby enciphered signals transmitted over an outgoing lineare deciphered by the printer to print a plain English home record atthe'tra'nsmitting station and in which the same;-

key'tape is used for both enciphering and deciphering purposes. 4

The invention may be more readily comprehended by reference to thedetailed description which follows when read with reference to thedrawings in which: Fig. 1 is a front sectional view, taken along line;

l|' of Fig. 4, in section, of a keyboard con.-:

trolled transmitter particularly illustrating the transmitter used inthe invention;

Fig. 2 is a detail view of a portion of'the ciphering mechanism;

Fig. 3 is a schematic circuit particularly designed for use with theciphering mechanism illustrated in Fig. 1;

Fig. 4 is an end view of the keyboard controlled transmitter taken alongthe line 4--4 of Fig. 1;

Fig. 10 is a detail view of the coding magnets and armature levers usedfor the printing ciphering operation taken on the line i 0-10 of Fig. 8;

Figs. 11, 12, and 13 illustratedifferent positions of the selectorswords and ciphering bars for the printing operation;

Fig. 14 is an illustration of the circuit used to control the codingmagnets; and

Fig. 15 is a modified form of the circuit designed for use with theinvention.

Referring particularly to Figs. 1 to 6, inclusive,-

the portion of the first embodiment of the invention dealing with thekeyboard controlled be had to the patent. of S. Morton et al., alreadyreferred to, and'for specific details of operation of the keyboardcontrolled transmitter per se, ref

3 erence should be had to the United States patent of H. L. Krum, No.1,595,472, dated August 10, 1926.

In Fig. '1 of the drawings a cast metal base is indicated at 21 uponWhich'is mounted both the keyboard transmitter and the printingapparatus with which the present invention is concerned. The keyboardtransmitter is controlled from a keyboard, not shown, wherein-depressionof a key lever 22 governs the positioning of the five permutation bars23 housed within the base casting 2 5, either to the right or leftposition. As shown in Fig. 1 the foremost permutation bar 23 is in itsleftward or marking position With the dotted line or spacing IDOSitilTnof permutaton bar 23 being indicated at 2 1.

Each permutation ba 23 carries a pair of pins 25 between which ispositioned a depending arm 26 of a selecting finger 2'! which is pivotedabout the rod 28. Pivotally mounted to each finger 2? at 2 S1, is a link3:! wh'ch carrie'sia pin 32 designed to in an 'a'rcuate slot '33 termedon a transmittin lever as. 'Fach transmitting :lev'er as is pivoted on:a rod 35 and is f the conventional type wherein it closes an associatedcontact pair 35 when its .lug L3? is pe mitted to enter a notch 33 of an'assoc'iated'transmitting carh't e In ad'- dition to the fivetransmitting xcams :39 the usual sixth start stop cam 18 it'Fig. *4) andcontact op crating lever l9 are provided. It may now be seen that when akey lever 22 moves a permutation bar 23 to the right or spacing positionselec't'ng finger "2 7 will pivot at '28 ina counterclockwise directionand when a permutation 'bar 23 moved to the shaft an opposite :eiliectwill be produced.

Also mounted within the "base casting 21 :below permutation bars 23 arelive :cip'heri-ng bars M which are under the control of five "codingmagnets 42, as will now be described. Thezcodingmagnets "t2 control theposition of associated arr-natures -53 which -are pivoted at 44. Upperextensions &5 of armatures 43 engage 'nct'ches 'llt of *eiphering barsSprings til "attached "to armatures 53 are normally effective to retainiciph'er bars at in their leftward or spac'ng position. When aparticular coding magnet 92 is energized it will attract its armature 43about its pivot 44 to force its associated ciphermg "bar 4! to ther'ght, as shown in '1, to the dotted line markin position indicated at417 Mountedpn each cipherin'g bar M are a pair of pins 18 which engage alever 49 :pivotediat 5'! the "free end "of which isnestedthe bifurcatedend 52 of a c'phering lever 53. Each "ciphei ing lever 53 is provided atitsu pper end with a :la' orally exten'din'g arm as having a notch 55designed to cooperate with the :pin B-Z-Icarri'ed by arm 31 or selectingfingerfl. It s now SeenFigs. 5 and 6, that if "ciphering bar 31ism-rived to its right, in response to a marking impulse received by itsassociated code magnet lever '49 will pivotin a clockw'se directionthereby pivoting ciphermg lever 53 in a counterclockwise position. If,however, its associated 'c'o'de magnet '62 receives spacing ornon-energizin .impulsa ciphering lever 53 will be retained in aclockwise pUsitiQn FigJZ.

From the fore'going description it is evident by an inspection of Pg. '7that unlike conditions of pins 32 carried by selecting fingers '21Withrespectto the notches "-55 of arms 54 of ciphering levers 53 "willpermit associated transmitting levers :34 to pivot at 35 when its lug31-is allowed to enter notch 38 of an asso ciated cam ts as' cam to theleft in its cFp'hering position as illustrated in Fig. 3. This operationcauses extinguishment of green signal lamp 62 and illumination of redsignal "lamp 63 over obvious circuits to indicate that a clpher ingoperation is taking place. The code magnets '62 are controlled by meansof a key tape 64, which is sensed by sensin levers 65 which controltransmitting levers 6% to thereby operate associated eontac-tipajrsii iin the usual manner.

Since there is no coding permutation set up by the magnets 32 at thecommencement of :a cipheri ng operation, the first signal transmittedwill be "a .plain English signal'which forms no part of the message andis transmtted solely to condition the ciphering mechanisms forsubsequent operations. When this signal is sent, 1 9 i rence to Fig. 7will show that selecting finger 2! and pin 32 thereon will :perform itsnormal function since as shownat Aland Bin Fig. 7, all ciphering leverswill be their spacing positions as no code magnets are energized. Inother words, a plain Englsh signal will be transmitted.

when the first signal :is sent by -operation of the keyboard, sleeve 56is released by 'a single revolution clutch infithenconventional manner.i

When this :occurs, locking lever 96 will pivot at 9?! under influence ofspring 99 in a counterclockwise direction and by means of its blade 98block movement of selecting fingers 2:7 and cipher-mg levers 53through'cooperation with lugs '68 carried by selecting fingers 2! andwith lugs es carried byar ms 5 50i ciphering levers 53.' At this timeapex '5'! of cam5'8 move in'a counterclockwise='direction, as viewedinFig. 1, and follower 59 "carried by locking lever 25 drops to the lowpart *of the cam. Thus, during transmission of the signal by thesequential operation of contact pairs 36, selecting fingers 2i andci'phering levers 53' are held stationary. It should be "remembered thatin a keyboard transmitter of the type disclosed in the present inventionthe permutation bars 23 are set immediately upon depress-ion of a keyprior to the operation of locking lever '95 and a single revolutionclutch not'sho-wn is operateii which releases cam sleeve '56 for asingle revolution. v

Simultaneously with the operation of locking l'ever "85, 'con'ta'ct pairH mounted with an insulating portion l-Z of blade 33 thereof resting onlooking lever 96, are closed and in so closing ass st'l'ocking lever96in its counterclockwise pivotal-movement, since normally in the restposition of '58 the longer blade 3-3 :of the contact pair I! :is undertension.

Gl'osur-e of-contact pair ll provides an obvious circuit for clutchmagnet T l which becomes energized and which controls a conventionalsingle revolutionclutehynet shown, and thereby releases cam sleeve :15for asing le rotation. Five cams l6 med to cam sleeve lb-are each cutwith a notch l i at a position timed approximately with the No. 3impulse of the keyboard transmitter. n sixth outgoing line.

cam 18 is also provided which is cut with'a notch 19a correspondingapproximately to the No.2 impulse of thekeyboard transmitter. Thefunction of the sixth cam 13 is to control the locking circuit for thetransfer relays 19 which initially become energized by closure ofselected contact pairs El depending on the key signals afforded by keytape 66. This initial circuit extends from battery, through switch 6|,through the winding of relay '59, over conductor 8!, through closedcontact pair 6'! and over conductor 82 to ground. When front armature 83is pulled up by relay 19 an obvious locking circuit is providedextending over conductor 84 and through closed contact pair 85.Operation of back armature 8B of a particular relay i9 is effective toprovide an obvious circuit over conductor 8? for energizing codingmagnets 42.

-When cam sleeve 75 is released for rotation upon energization of clutchmagnet 74, cam i8 will function approximately during the No. 2 impulseof the keyboard transmitter to open contact pair 85, de-energizingtransfer relays 19 by breaking the above described locking circuits andcausing therewith de-energiza'tion of coding, magnets 42 and erasure ofkey signals stored therein. However, as already pointed out, no codingmagnets 42 are energized during thetransmission of the first signal butfor subsequent signals opening of contact pair 85lwill produce thedesired results. Immediately following the opening and closing ofcontact pair 85, selected sensing levers 65 which are sensingperforations in tape 54 allow their associated transmitting levers 56 toclose contact pairs 61. This enables the energization of coding magnets42 according to the first key signal. Ciphering bars 4! may move totheir selected positions as locking lever 96' is raised by the follower59 when the rest position of sleeve 56 is approached.

When the operator depresses a key to send the first enciphered signal, akey signal will have been stored in coding magnets 42 and ciphering bars4| will have been set accordingly. I The depres ion of the key willimmediately shift permutation bars 23 in accordance with the originalsignal. The locking lever 95 will now look the selecting fingers 2i andthe ciphering levers 53 during transmission of an enciphered signal toan The operation of transmitting levers as will of course be determinedby the joint control exercised by electing fingers 2'? and.

ciphering levers 53, as graphically represented in Fig. 7, thusensuring, the transmission of an enciph ered code signal.

With particular reference to Figs. 3 to 14, inelusive, the printerciphering mechanism used for deciphering incoming signals transmitted bya keyboard transmitter, such as disclosed in Fig. 1, will now bedescribed. Numeral lfll indicates generally the printing portion of acombined printing telegraph apparatus similar to the apparatus disclosedin the patent of S. Morton et al. referred to above. In this type ofprinting apparatus, incoming signal-slare received by a selector magnet502 which operates an armature Hi3 accordance with received signalswhich in the instant case are enciphered signals being received from adistant station. Connected with armature I03 is an armature extension184 whose arms Hi5 and W6 are designed to cooperate respectively witharm 1.81 and I98 of five swords me. In each operation of the swords theyare moved back and arms. In! or. 508 respectively engage either arm !05.or lllfiof armature extension 6' "l4 according to incomingsignalsjr'es'ulting in the shifting of the swords to either their mark-'ing or spacing position'so that onthe forward movement thereof thepointed end of the sword will engage either surface ill or H2 of leversH3. The reciprocation of the sword use is accomplished by means of a camsleeve, not shown, which is controlled by a conventional singlerevolution clutch. This type of selector is well known in the art andits operation is completely disclosed in the Morton et al. patent.

Ordinarily swords I09 control the operation of the printer selectorvanes H4 by means of a series of T-levers not shown in the presentinvention since the type of printing telegraph-apparatus hereindisclosed is designed for perform-' ing deciphering operations inaddition to operating to receive plain English signals. Levers H3 whichare pivoted at HB; and have a limited movement afforded by the pin 1 l5and slots H6, have a projecting end H1 designed to cooperate with aprojecting end I I8 of ciphering slides l l9. The relative positions ofthe projecting ends ,H'! and H8 will determine whether a vertical slide|2l which has a rounded arm E22 in engagement with slot I23 of'ciphering slides H9 will be permitted to move up, when the vanes I I4are not locked, by bell cranks B24 pivoted at I25 and normally urged ina counterclockwise direction by springs I26. The positions of slides H9are governed by operation of armatures lZB'a of key coding magnets 2! towhich they are pivotally' attached at I28. Armatures lzfia are nor mallyurged in a clockwise direction as viewed in Fig. 8 about shaft [29 bysprings I553. Articulatedto each vertical slide l2! by bifurcation @253are the vanes H4 which are normally in their spacing position but pivotto a clockwise or marking position when an associated slide l2l is permitted to move upward. It should be mentioned at this time for the sakeof clarity that the normal position of the slides H 9 to the left is thespacing position while the position to the right is the markingcondition. Likewise, the position of levers H3 to the right is themarking position while the position to the left is the spacing position.-When a, nonblocking or marking condition exists with respect toprojections l I! and l 98, slides ill will be enabled to move up,thereby actuating associated vanes H4 to their marking positions.

that slides lZi will not be able to move up and the associated vanes H4will remain in their spacing position. These blocking and nonblockingconditions are illustrated in Figs. 8 and 11 to 13.

For controlling the ciphering operation the printing cam l3! mounted onsleeve 232 (Fig. 9) is utilized: Printing cam i3! is standard part ofprinting telegraph apparatus of this type and controls the operation ofthe printing bail, not shown, which operates a selected pull bar alsonot shown, the selection of which is controlled by the printing vanesHQ. In the path of the high part of printing earn it! is normallypositioned-a follower I33 carried by lever lei which is pivoted near itsrear'extremity at 535. The front end of lever I34 isslotted at 136whereat it is engaged by a pin I31 supported on a T- shaped lever I38which includes a bail it! which overlies arms 22 of the vertical slides52!. T shaped lever I38 is normally urged in a clockwise direction asviewed in Fig. 8 by means of spring 163. The T-shaped lever 138 ispivotally con- If like or blocking conditions exist between projectionsH'l and H8 it is apparent area-sec nected at In to a, rearwardlyextending .lever M2, the rearward extremity of which normallyholds 'acontact pair I 4:3 in its open position.

The circuit shown in Fig. 14 .for controlling the operation of codingmagnets I121 will now be described. For deciphering incoming signals, ;akey tape I44 is provided which is identical with the key tape at thetransmitting station and occupies the same relative position. To senseperforations in tape I44 a series of tape sensing levers M5 are providedwhich control the operation of transmitting levers I46 in the usualmanner to permit contact pairs M1 to closeor remain open depending uponthe permutation afforded in key tape I44.

When a particular sensing lever :I 45 :moves into a perforation ailowingclosure of a contact pair M a circuit is made for an associated transferrelay I48. Attraction of front armature I49 provides an obvious lockingcircuit for transfer magnet M8 extending over common conductor I-5:I:and through contact pair 1-52 which is under the control of a sixth camI 53 notched :approximately for operation during receipt of the No. 2element or impulse by the receivingselector magnet IBZ. The fivetransmitting cams I154 which control contact pairs 1-41 are notchedapproximately for operation during receipt of the No. i element orimpulse by selector magnet I21. When armature 1550f transfer relay 148is :attracted an obvious circuit isprovided for-its associated codingmagnet I21.

In order that the invention may @be :properly understood a typicaldeciphering operation will now :be described. At the commencement of thedeciphering operation by prearrangement with the transmitting station,manual switch I56 will be moved to the left which extinguishes the greensignal lamp l5? and illuminates the red signal lamp I53 indicating .adeciphering operation is taking place.

It will be recalled that to start the keyboard transmitter disclosed inFig. 1 into operation a plain English signal forming no part of themessage is transmitted over the line. This :plain English signal 'hasthe additional function of conditioning the printer tor subsequentdeciphering operations. When this-first signal .is received by selectormagnet m2, swords H39 will be positioned according to the signal acode'combination received. Towards the end of the reyolution of the camsleeve, not shown, controlling the swords I39, cam sleeve I32 will bereleased by operation of its clutch throwout :lev'er 130 which is underthe control of the sword cam sleeve. Upon the first release of comsleeve I. 3-2, printing bail cam I3I rotates and its high :part engagesfollower I33 .of lever 43 wh-ichr-now pivots about its pivot 1-35 aclockwise direction, and through the engagement of its 'slot 136 withpin it] carried :by T-lever 138, pivots 'T-lever I 38 in acounterclockwise direction, lifting the bail i-ii-i fromhol'dingiengagement with arms 122 of vertical slides 12!. Selectedvertical slides 124 will now move up through operation-of bell cranksI24 by their springs I26 and operate vanes FHA accordingly. In thisconnection it should be remembered that 'atthe commencement of aciphering operation all ciphering slides x-II'Q are :in their leftwardor spacing position, in which position levers I I3 will be set to.permit plain English signal code combinations to be transferredtothevanes H4.

Shortly after the vanes I'I-i4-are setforith'e signal code combination,the function :bail, not

- ciphered signal is being received by selector magshown, locks thewanes during the printing operation. The function bail is controlled bya function bail cam I 53 (Fig. :9.) which is mounted upon the cam sleeveI32. In the latter part of the revolution of cam sleeve I32, after the.printing operation is performed, vanes EM are again unlocked, but atthis time bail 14'! of T-lever I 38 is prepared to assume a positionresting on arms I22 of vertical slides 'I2I holding the vertical slidesI2I- in their downward position. This is due to the fact that .in thelatter part of the revolution of printing bail cam Hit, a low partthereof is presented to the follower I33 of arm 1.34 and spring I63therefore functions to pivot T-lever I 38 in a clockwise direction.

It should be remembered that whilecam sleeve I32 is rotating, a newsignal or the first ennet I02 and the swords I09 are being set to a newposition. At this time levers H3 may not be able to move to their newposition due to the fact that the vanes may be locked and hail AI ofT-lever I38 is in its upward position, permitting some projections .'I Hand M8 to block each other. However, since swords 'ii il reciprocate andpivot in each cycle of the operation, in their backward stroke they willacquire their new settins and in their forward movement rest againsteither surface .iII or surface H2 of levers H3. When vanes H4 areunlocked and hail MI moves to its downward position upon the secondrelease of .cam sleeve N2 the swords 169 may now position levers H3 inaccordance with the first enciphered signal. Therefore, by reason of thelocking of the vanes H4 :and operation of bail I4I a new character maybe selected while the previous character is being printed, thusproviding a signal overlap arrangement as is usual in this type ofprinting telegraph apparatus.

As cam sleeve I32 started to rotate, towards the end of the reception ofthe first or plain English signal by selector magnet Hi2, T-lever i 38was pivoted in a counterclockwise direction thereby moving therearwardly extending lever ,I 412 to the right permitting closure ofcontact pair I43. This provides an obvious circuit for a clutch magnetISI (Fig. .14) which causes operation of a single revolution clutch, notshown, releasing cam sleeve I62 for operation. It should be borne inmind that at this time the second signal or first enciphered signal codeis being set up by swords E09 as explained. Approximately duringreception of the No. '2 impulse by selector magnet Hi2 cam 1.53 willopen contact pair I52 breaking the locking circuit extending overconductor 151 for transfer relays M8. However, since none of the relays1-48 are energized during reception of the first or plain English signalno circuit is actually broken but on subsequent operations previoussignal 'codecombinations stored in transfer relays I48 will be erasedand cause a correspond ing erasure of the signals stored in codingmagnets !21. Approximately during reception of the No. 4 impulse .byselector magnet 292 sensing levers I45 will feel for perforations in thekey tape I44 set to the same position on the identical key tape at thetransmitting station and accordingly contact pairs Ml will be permittedby cams I54 to close in the permutation afforded by the key tape I44 atthis time. Selected transfer relays I48 will thus be energized andimmediatel lock up since contact pair I52 is again closed at this time.As selected code magnets I2? are energized at this time they attractarmature levers 126a in a ;counterclockwise direction about the rod I29,thereby tending to move associated -'ciphering slides II9 to the rightor marking position. Since the vanes I I4 are unlocked approxiinatelyduring the receipt of the No. 4 impulse 'by selector magnet I02 whilethe tape Sensing operation is being performed, selected slides I I 9 maybe temporarily restrained-from operation depending on the exact timingif their projections H8 interfere with the projections III of levers H3.

sleeve I32 is released for operation, cam I3I operates against followerI33 of lever I34 to thereby pivot T-lever I38 in a counterclockwisedirection removing bail MI from the path of arms I22 of selectedvertical slides I2I permitting them to assume their upward position.Shortly thereafter, the vanes H4 are locked and retained intheir'locking position during the printing operation in which adeciphered plain English signal will be printed. The decipheringoperations will continue in the same manner for the remaining portion ofthe message.

In the just described form of the invention for accomplishing key codingoperation two key cod ing devices are employed in the form of key tapes,one being used for enciphering or transmitting purposes and the otherbeing employed for dc ciphering or receiving purposes. In a modificationof the invention there is provided a control circuit whereby a singlekey ciphering device in the form of a key tape sensing mechanism'maybeused for both enciphering and decipheringoperations. With referenceparticularly to Fig. 15 of the drawings. this modification will now bedescribed.

Numeral I85 represents a local station which includes a combinedkeyboard transmitter I86 and printin receiver IIH while a distantstation is represented as numeral I68 and includes a combined keyboardtransmitter I89 and printing receiver I 18. This type of printing teleraph apparatus is disclosed in the S. Morton et a1; patent previouslyreferred to above. It is understood that in addition to the standardprinting telegraph equipment each station will be equipped withidentical key'coding devices. By this modification of the invention atransmitting station will send enciphered ignals to an outgoing linewhich will be repeated in the receiving circuit of the transmittingstation and deciphered to thereby print a plain English home record;

A key ciphering tape is represented by numeral Ill and controls theselective operation of sensing levers I72 which govern the operation oftransmitting levers I18 and is thereby effective to permutativelyregulate the closure of associated contact pairs I14 in accordance withkey code signals. For enabling the permissive operation of transmittinglevers I13, there are provided the usual transmittin cams I15 which inthi instance are all notched at I16 for approximately the No. 5 impulseposition and are mounted upon thecam sleeve I11, Cam sleeve I11 is underthe control of clutch magnet I18 which releases a conventional singlerevolution clutch,

not shown, upon closure of contact pair I60 when clutch throwout leverI38 which releases cam sleeve I32 (Figs. 8 and 9) 'is operated. Theclosure of selected contact pair I14 enables the selective operation ofprimary storage relays I88 according to key signals under certain,circuit conditions to" be later described. The primary storage relaysI88 selectively govern the operation of double wound relays I19 and I8I,which respectively control'the energization of selected transmittercoding magnets I82 and selected receiver coding magnets 33..

In addition to the five transmitting cams I15 there are provided on camsleeve I11, cams I84, I85, and I86 which respectively control makebefore break contacts I81, I88, and contact pair I89 by means of levers-I9I, I92, and I93, respecpulse position. These so called impulsepositions frepresent positions in the rotation of the cam sleeve I 11which correspond to the usual five positions and start-stop positions ofthe Baudot code. I

When sensing levers I12 sense perforations in the key tape I1I, selectedcontact pairs I14 will be closed energizing selected primary relays I89over conductors I94 under certain operating conditions which will laterappear. When a pri- 'mary relay I88 is energized a locking circuittherefor is provided through attracted armature 495, over conductor 498and through contact pair I89 controlled by cam I86. Attraction ofarmature I91 by a primary relay I88 prepares a circuit for transferringa selection from a primary relay I88 to double wound relay I19, when thenormally open pair of the make before break contacts I81 are closed,over conductors I98, through armature I91, over conductor I98 andthrough the left winding of double wound relay I19.

Energization of a double wound relay I19 causes the transfer of theselection to an associated transmitter coding magnet I82 by attractionof armature 295 while attraction of its armature 208 provides a lockingcircuit for double- Wound relay I19 extending through its right winding,through armature 288, over conductor 201 and through the normally closedcontact pair of the make before break contacts I81.

Attraction of armature 288 by a primary relay IBB prepares a circuit fortransferring a selection from a primary relay I88 to a double woundrelay I8I, when the normally open pair of the make, before breakcontacts I88 are closed, over a conductor 289, through armature 288,over a conductor 2H and through the right winding of double wound relayI8I'. Attraction of armatture 2I2 by a double wound relay I31 transfersa selection to associated printer receiving coding magnets I83 whileattraction of its armature 253 provides a locking circuit for doublewound relay I8I extending through its left winding, through armature2I3, over conductor 2I4 and through the normally closed contact pair'ofthe make be. fore break contacts I88.

To facilitate a ready understanding of this modification of theinvention, a description of a typical ciphering operation will now beundertaken. At the commencement of ciphering operations manual switch2H5 is moved to the left extinguishing green signal lamp 2E5 andilluminating red signal lamp 2I8, over obvious circuits and indicatingthat a ciphering operation istaking place. In order to condition boththe local station I and distant station I88 for ciphering operations twoplain English signals chosen at random are first transmitted which formno part of the message proper. It is necessary that these two plainEnglish signals be transmitted in order that the control circuit. beconditioned to aiford key ciphering signal. code combinations for boththe transmitter and receiver at a given station. All signals sent overthe line. 213 to distant station. I83. will be repeated by the selectormagnet I02 at the local station and. printed. after being deciphered bythe receiver Ill I.

Upon the transmission of the first plain. English signal, cam sleeve1-32 (Fig. 9) is released as explained by operation of clutch thro-Woutlever I36 which immediately results in the closure of contact pair I66;providing anenergizing circuit for clutch magnet I18 extending overvconductor I-9ll, thereby releasing cam sleeve I'll. When cam sleeve I1!is released, make before break contact I81- operates to erase theprevious selection existing in code magnets. I82 duringthe. startinterval, of cam sleeve I." by opening the. looking circuit for doublewoundrelays [79, thereby causing de-energization of the. associated codemagnets I82. However, during the first revolution of cam sleeve I'I'lnocoding magnets [32 are yet energized. When make before break contactI8'l operates to erase the selection previously existing in code magnetsI82, it. also functions toacquire a new selection for the code mag.-nets I82 from primary storage relays I80 but again it must be rememberedthat at this time. no primary relays I36- are yet energized. Make be-.=fore break contacts. I88 function in the same manner as contacts I8? butduring theNo. 2 impulse period of cam sleeve ll]. During the No. 3impulse period, contact pair I89 opens to erase the selection existing(if one had existed) on primary relays I80. by breaking its lockingcircuit When cam sleeve Ill reaches its No. 5' position as the sensinglevers I72 operate, the first ciphering selection will now be acquiredfor primary storage relays [80.

When the second plain English character is transmitted, contact pair I69will be closed by clutch throwout lever I3fi as described releasing camsleeve IT! for its second revolution. During the start impulse, makebefore break contacts I81 operate as before. but now enable the doublewound relays I19 to acquire the selection existing in, primary. storage.relays. I80. and transfer the first key ciphering selection totransmitter coding magnets I82 which look up asv previously described.Make before break contacts I88 will perform a similar function forreceiver code magnets I83 during the No. 2 period of opera.- tion of camsleeve ITT. During the No.3 period, contact pair [.89 will open to erasethe selection existing in the primary relays I80. which Will acquire thesecond ciphering. selection from keytape I'Il when cams H5 reach the No.5 position as tape sensing levers H2. operate.

Now when the keyboard. transmitter Ififiis operated a third time,ciphering-bars M (.Fig. 1.)- Will have been set to the positionsrepresentative of the first key ciphering signal and accordingly thefirst enciphered signal will be transmitted. Likewise ciphering. slidesH9 (Fig. 8) will. have been set to. positions. representative of thefirst key signal and. receiver IDI will function to decipher the. firstenciphered signal repeated; by selector magnet I92 to print thecharacter. in plain English form. As cam sleeve. Il l is released forthe third time it should be mentioned that the make beforebreak contactI88. is timed; to operate after the printing vanes lock; tohis sure thatthe same key signal used for enciphering will beused for deciphering;The, cycles of operation described. will. now be-repeatedas theremaining portion of the ciphering operation proceeds. It is obviousfrom an inspection of the circuit shown in Fig. 15 that thecipheringsystem may be operated in either direction of transmission, with; theidentical. key tape at each station. occupying the; same positions.

Various changes and modifications may be made. in the above describedinvention without a. departure from the spirit and. scope of the;invention as defined inv the following claims.

What is claimed is:

1. A ciphering selector for a transmitter: com

prising a plurality of slidable permutation bars operable according tooriginal code combinations, an equal number of selectingt leverscontrolled by said permutation bars, a like number. of; key signalresponsive code magnets, a series oi slidable ciphering bars controlledby said coding magnets, a plurality of ciphering levers individuallyassociated with said ciphering bars, a set of transmitter leversoperable under the joint control exercised thereover by said selectingfin.- gers and said ciphering levers, and means con;- trolled during.the transmission of one resultant signal code combination by said.transmitting levers for energizing said code magnets in; accordancewith. the next key code combination for thereby setting said cipheringbars. for: the next operation. 2'. Ina ciphering selector for a printer,a selector magnet for receiving incoming signals. in.- cluding a set ofswords controlledby; said. magnet, an equal number of levers controlledby said swords and having interfering members carried thereby, a set of,key signal controlled. coding magnets, a plurality of ciphering slidesoperable by said coding magnets. and having interfering members, a set.of printer selector vanes, means controlled by the joint positioning ofsaid interfering members for determiningv the ultimate. position ofsaid. printer vanesand. means operable during the utilizationrof asignal code combination provided by said printer selector vanes for aprinting function. for: energizing. said code: mag.- nets accordancewith the next key signal cod'e combination for thereby setting saidciphering slides for the next operation.

3a Ina. ciphering transmitter, in. combination, a plurality of. slidablepermutation bars operable according to originalcode combinationsan equalnumber of selecting fingers controlled by said permutation bars, a likenumber of; key signalre sponsivecode magnets, a series of sl idableciphering. bars controlled by saidcoding: magnets, a pluralityof,ciphering levers individually associated with. said ciphering bars, and,a circuit arrangement operable during the utilization of. a: key codecombination for one operation for erasing the previous key .codecombination established by said second mentioned members and. preparinganew'key code combination therefor for the next operation.

4., In a telegraph receiver, in combination, a selector including aselector magnet for-receiving incoming signals and a set'of swordscontrolled by said. magnet, an. equal number of levers havinginterfering. members carried. thereby and controlled by said swords, a.set of key code combination; controlled coding magnets, a pluralityofciphering slidesv operable by said coding magnets and having interferingmembers, a set of printer selector vanes, and acircuit arrangement operable during the utilization 'ofa code combination established by saidprinter. selector vanes for aprinting operation for erasing the previouskey code combination existing in s" (1 code magnets a new key codeination thereset of code magnets:

tus, a set of cod receiving -appa1'atus, a singlekey coding device forcontrolling both of said sets-or magnets, a series oftransmittinglevers, mechanical means controlled byfsaid first mentionedset ofmagnets for varyingthe normal operati nj-of said transmitting leversaccording to keylcdde combinations furnished lcy said key codingd 'e forproducing resultant-.enciphered signal a selector magnet for receivingsaid resultant 'enciphered signals, selector" members contrqlle'gby saidselector magnet, a series of printer selector vanes, andmechanical'means controlld by" said second mentioned'set of magnets an'dcooperating with said selector: members for varying the normaloperationofsaid printer selecl vanes according to-"identi caI key codecomb nations for producing resultant deciphered signals.

6. A combined transmitting and receiving apparatus, aset of codemagnetsifor the transmitting apparatus, a set of coidefinagnets for thereceiving apparatus, a single'ikey. coding device for controlling bothof saidsets of, magnets, a series of transmitting levers, mechanicalmeans controlled by said first mentioned set of magnets for varying thenormal operat of said transmitting levers according to il t" lcodecombinations" furnished by said key cod g devicefor producing resultantenciphered rials, a series of printer selector vanes, and mechanicalmeans controlled by said second mentioned set of magnets for varying thenorma operation of said printer selector vanes according to identicalkey code combinations for producing resultant deciphered signals and a,circuit arrangement for controlling said key coding device.

7. A combined transmitting and receiving apparatus, a. set of codemagnets for the transmitting apparatus, a set ofcode'inagnets for thereceiving apparatus, a key trolling both of said sets 9 mitter includinga set of t means under the control I 0 set of magnets for altering I, ofsaid transmitting levers receiver including a set of printer-selector vI x means under the control of said second men onedset of magnets foralteringthe normal operat on of said printer selector vanes, and acircuit arrangement for said ra rfsfmitting levers, id'rirst mentionednormal operation i4 key coding device for providing key codecombinations for each of said sets of magnets and prior thereto erasingkey code combinations previously existing in said sets of magnets.

8. In a combined telegraph transmitting and receiving apparatus, atransmitter including a set of transmitting levers, a receiver includinga set of printer selector vanes, a key coding device for altering thenormal operation of said levers and vanes, and a circuit arrangement forproviding key code combinations for said key coding device including aset of primary relays for stor ing key code combinations, a set of codemagnets for said transmitter, a set of code magnets for said receiver,means to transfer key code combinations from said primary relays to eachof said 7 set of code magnets, and means to erase previously existingkey code combinations in said primary relays'and both of said sets ofcode magnets, said transfer means and said erasing means being properlytimed to enable the use of identical key code combinations by saidtransmitter and said receiver for any given signal code combinationtransmitted by said transmitter.

9. A telegraph apparatus including an enciphering and a decipheringmeans, a single key coding device for providing key code combinationsfor both of said means, a set of primary relays for storing key codecombinations, a set of key code magnets for said enciphering means, aset of key code magnets for said deciphering means, means to transfersignal code combinations from said primary relays to each set of saidkey code magnets and means to erase previously existing key codecombinations in said primary relays and both of said sets of codemagnets, said transfer means and said erasing means being properly timedto enable the use of identical key code combinations by said encipheringand said deciphering means for any given code combination.

MARTHA W. c. POTTS, Erecutrja: Under the Last Will and Testament ofLouis M. Potts, Deceased.

: REFERENCES CITED The following references are of record in the .j fileof this patent:

UNITED STATES PATENTS Number Name Date 2,317,995 Krum May 4,1943

2,406,829 Haglund et a1 Sept. 3, 1946 e 2,449,789 Reiber Sept. 21, 1.948

